--We continued our studies of the CA2 region of the hippocampus where the Oxtr and Avpr1b are located. The CA2 area is an important, although relatively unexplored, component of the hippocampus. We are studying the role of various receptors and in the CA2 by crossing floxed receptor lines with Oxtr and Avpr1b-cre expressing lines. We are studying the resultant behaviors, especially as they relate to aggression and learning and memory. --We are continuing to use optogenetics and expanding to electrophysiology to study the role of the CA2 in behavior. We are examining the input to CA2 from other regions as well.